The present invention relates generally to antennas. More particularly, the present invention relates to antenna assemblies having a deformable portion that may be fixed within a gap or crevice, particularly a gap or crevice formed between two opposing edges of an closure. Even more particularly, the present invention relates to low profile antennas having a deformable portion for use in roadways, sewer manholes, and other applications where a low profile and a deformable portion are desirable.
The collection of data from sanitary or storm sewer networks, air handling systems, and other underground or enclosed systems or networks having access apertures, and/or closures, has become increasingly common and useful. For example, in an underground sewer network, flow monitors may be used to collect data such as depth, volume, velocity, and/or other measurable parameters in a certain location. When such monitors are used, it is often desirable to collect the data in a central location, such as a remote computer or data collection system, so that data from multiple monitors can be analyzed, stored, processed, compared, and/or presented to a user. Because of the impracticality of connecting monitors that may be located throughout such a sewer or other network to a central processor via direct wiring, it is desirable that such monitors transmit their data to a remote computer through a wireless communications medium.
The application of wireless technology to transmit and/or receive data from and/or deliver data to flow monitors within enclosed systems requires a suitable antenna for reception and/or transmission. Typically, the monitors are installed in the interior of enclosed systems or networks near an aperture or closure which provides access to the interior of the enclosed system or network. For example, sewer flow monitors are typically installed in a sewer network inside or near manholes in order to provide easy access to the monitor for installation, maintenance, and repair. Thus, the monitor may communicate with a remote unit outside the network via a wireless transmitter that is also located near or within the manhole. However, if the transmitter""s antenna is mounted so that the antenna is below the manhole""s cover, substantial losses in signal strength, such as radio frequency (RF) energy losses, will result from factors such as signal attenuation and the fact that the antenna is mounted below the ground plane.
One solution to the problem of antenna placement is to mount the antenna above the ground, outside of the manhole. However, conventional antennas normally require a mast or pole type of mounting. Thus, conventional antennas have an elevation that renders them undesirable for use in many locations, such as roadways and sidewalks, where vehicular and/or pedestrian traffic will flow. Examples of such antennas may be found in U.S. Pat. No. 5,877,703, to Bloss et al. Such antennas are subject to abuse from, and may be damaged by, roadway traffic, such as cars, trucks, buses, and other vehicles, as the traffic drives over them, directly placing substantial loads on the antenna. Other roadway vehicles such as snowplows can cause even more damage to an antenna that is raised above the roadway.
In addition, many such antenna installations require modification to the manhole cover, such as the drilling of a hole, or cutting a groove in a manhole cover or roadway surface, to connect the above-ground antenna to the underground flow meter, or require positioning the antenna within an existing groove of the roadway surface and affixing the antenna therein with a sealant. An example of the latter method is found in published U.S. Patent Application No. US-2002-0180656-A1, the disclosure of which is incorporated herein by reference. Such holes and grooves are generally large, as they are also used as a means to secure the antenna to the manhole and/or to connect the antenna to equipment below the manhole cover, such installation processes are costly and time-consuming, and the installation of multiple antennae requires multiple installation procedures.
Typical antenna assemblies found in current practice are not suitable for installation within an existing gap or crevice in the outer surface of the enclosed system or network. Such a crevice is found commonly in an aperture or closure which may be opened to provide access to the interior of the enclosed system or network, such as the crevice between a manhole cover and the surround in which the cover is seated during normal traffic use. Typical antenna assemblies are not sufficiently flexible or deformable to resist the stresses placed on an antenna positioned within such a crevice. Apertures into enclosed systems typically have closures, such as a cover that fits closely around its periphery within a surround, and abuts to an inner seating rim or lip of the surround that prevents the cover from falling into, or otherwise penetrating, the enclosed system. A manhole cover, for example, is a heavy iron or steel disk that sits within such a surround. The heavy weight and hard-edged surface of the manhole cover puts a great deal of mechanical stress on an apparatus pinched between the cover and the surround, particularly the inner lip portion of the surround. Since a conventional antenna assembly is not deformable or elastic, a conventional antenna assembly cannot resist this stress when the cover is removed from or inserted into the surround, and will tend to break under the stress. Furthermore, conventional antenna assemblies are not suitable for the harsh environmental conditions often found around apertures into, or closures of, enclosed systems, such as the street environment around manhole covers.
Elan Industries, Inc., Hickory Hills, Ill. (www.elanindustries.com), discloses a copolymer manhole cover that includes an integral antenna and cable. This application requires retrofitting an existing manhole with the new cover. Hence, the Elan product requires that the size and shape of a manhole be known in advance of using the device. Since the existing manhole cover is replaced, this process is wasteful. As the antenna is not separable from the manhole cover, another new manhole cover must be employed, or the old cover must be saved and stored, if the antenna is to be removed from the manhole. Furthermore, the Elan product is not readily deformable to fit the variety of gap and crevice sizes and shapes that is found in the field; it must be custom-fabricated for each application. Elan does not disclose an antenna assembly that may be fixed in a gap or crevice that is not a manhole. The Elan product contains only a single antenna, thus making the installation of multiple antennae potentially complicated and costly.
Antennae, and antenna assemblies, having some degree of flexibility can be found in the patent literature. For example, U.S. Pat. No. 4,769,656 discloses an expansion band antenna formed of a woven conductive material that may expand and contract. U.S. Pat. No. 5,742,259 discloses a helical wire antenna that is flexible with respect to its long axis as a spring. U.S. Pat. No. 5,949,384 discloses an antenna apparatus having a wire loop within an elastic sheath that may be collapsed into smaller loops. U.S. Pat. No. 6,337,663 discloses a rigid printed circuit antenna having an elastic connector for connecting with the main board of a communication device. Finally, U.S. Pat. No. 6,501,945 discloses a cellular phone having an antenna assembly that includes an elastic conductor that makes electrical contact between a circuit board and a metallic coating on the interior of the phone to provide an insulating envelope. However, none of these antennae and antenna assemblies has the durability, deformability, and elastic qualities required for the application of providing an antenna assembly that may be installed in a crevice of an aperture into, or closure of, an enclosed system or network, which requires flexibility and deformability in multiple dimensions, impact resistance, weather resistance, and resistance to high mechanical stresses.
Accordingly, it is desirable to provide an improved antenna assembly, as disclosed herein, that overcomes the aforementioned disabilities.
It is therefore an object of the present invention to provide an improved antenna assembly for mounting in a gap or crevice, particularly a gap or crevice of an openably closed aperture or closure wherein the antenna assembly is flush with or slightly raised above one side of the aperture or closure, preferably the outside, and is connected to transmission lines disposed on the opposite side of the openably closed aperture or closure, preferably the inside.
Another object of the invention is to provide an antenna assembly for mounting between bricks or stones in masonry, or in a groove cut into a solid surface, preferably wherein the antenna assembly is flush with of slightly raised above one side of the masonry or solid surface, preferably the outside, and is connected to transmission lines disposed on the opposite side of the masonry or solid surface, preferably the inside.
An additional object of the invention is to provide an antenna assembly having at least one deformable antenna connected to at least one transmission line by at least one deformable conducting means, wherein the at least one deformable conducting means and/or at least one deformable antenna is suitable for being fixed within a gap or crevice, particularly a gap or crevice of a closure.
It is an additional object of the present invention to provide an antenna having a profile that reduces or eliminates the susceptibility for damage to the antenna resulting from persons or objects passing by the antenna, such as pedestrians, maintenance workers, roadway traffic and road-scraping implements such as snow plows, and the like, and that is deformable to reduce or eliminate the susceptibility for damage from the stresses resulting from the antenna assembly""s installation within a within a gap or crevice, particularly a gap or crevice of a closure.
It is another additional object of the present invention to provide an antenna having a profile that reduces or eliminates the risk of injury to pedestrians who might come into contact with the antenna (i.e., by tripping over it, bumping into it, becoming caught upon it, etc.). The height that is of a low profile is preferably about one-fourth of an inch or less, or even more preferably is flush with the mounting surface.
An even further object of the invention is to provide an antenna that is inconspicuous so as to be resistant to vandalism.
Another object of the invention is to provide an antenna assembly having multiple antennae, or multiple antenna subunits, within a single enclosure in order to provide an easy and cost-effective means of installing multiple antennae in one location.
In accordance with a preferred embodiment of the present invention, the present invention provides an antenna assembly, including: at least one antenna; at least one transmission line; at least one conductor for conductively connecting the at least one antenna to the at least one transmission line, wherein the at least one conductor is deformable; and a deformable membrane made from substantially non-conducting material, wherein the deformable membrane substantially encloses the at least one antenna and the at least one conductor, and at least partially encloses the at least one transmission line. The height that is of a low profile is preferably about one-fourth of an inch or less, or even more preferably flush with the mounting surface. The at least one antenna is most preferably deformable, as well.
In accordance with another preferred embodiment of the present invention, the present invention provides an antenna assembly, including: at least one communication means for sending and receiving radio frequency (RF) signals; at least one transmission means for transporting electrical signals; conductive means for conductively connecting the at least one communication means and the at least one transmission means, wherein the conductive means is deformable; and insulating means substantially enclosing the at least one communication means and the conductive means, and at least partially enclosing the at least one transmission means, wherein the insulating means is deformable. The antenna means is preferably deformable and has a low profile. The height that is of a low profile is preferably about one-fourth of an inch or less, or even more preferably flush with the mounting surface.
In the embodiment above, the communication means is preferably at least one antenna, more preferably at least one dipole antenna, and even more preferably at least one dipole antenna having elongated elements with a combined length suitable to provide an antenna electrically tuned to send and/or receive RF signals in close proximity to a traffic surface, as described below. The deformable conductive means is preferably a deformable conductive solid, liquid or gel, and is more preferably a deformable copper wire or ribbon, as described below. The at least one transmission means is preferably at least one transmission line, and more preferably at least one coaxial cable, as described below. The deformable insulating means is preferably a deformable rubber or plastic outer protective covering, as described below.
In a preferred embodiment, at least one antenna of the antenna assembly of the present invention is a low profile dipole antenna for receiving and/or transmitting radio frequencies that includes a first elongated element made from an electrically conductive material, a second elongated element made from the electrically conductive material, and a transmission line that is conductively attached to the first and second elongated elements by way of a conductor. The first and second elongated elements each have a height that is of a low profile and lengths that are substantially equal. Each of these elements is preferably deformable. The elongated elements are covered at least partially with a substantially non-conductive covering that is at least partially deformable.
Optionally and preferably, the first elongated element and the second elongated element are positioned to extend in opposite directions, form substantially a straight line, and are separated by a gap to provide a dipole antenna. Also optionally, the first elongated element and the second elongated element are sized wherein the substantially straight line has a length that corresponds to an operating frequency band of the at least one antenna and wherein the length provides an electrically tuned antenna that is configured to transmit and receive RF signals in close proximity to a surface.
In an alternative embodiment, the antenna assembly of the present invention may include at least one dipole antenna having first and second elongated elements separated by a gap, wherein the first and second elongated elements are positioned to extend in substantially opposite directions from one another and to form a circumferentially-curving line (i.e., a line corresponding to the circumferential periphery of a rounded cover or surround). In an even more preferred embodiment, the circumferentially-curving line has a length that corresponds to an operating frequency band of the at least one antenna wherein the length provides an electrically tuned antenna that is configured to transmit and receive RF signals in close proximity to a surface.
In accordance with the above-described embodiments, the antenna assembly includes at least one conductor, wherein the at least one conductor comprises a conductive solid material. Alternatively, the at least one conductor may comprise a conductive gel material, or even a conductive liquid material. A conductive gel or liquid material is preferably a gel or liquid containing conductive polymers, organic or inorganic salts, and/or metallic particles. A conductive solid material preferably includes a conductive metallic component. A solid conductor preferably includes copper, and may include a copper wire or ribbon. The conductive wire or ribbon may be coiled, repetitively folded, woven, mesh-shaped, have an undulating shape, or may have any other shape that provides flexibility, extensibility, deformability, and resistance to mechanical stresses, particularly stresses of extension and compression.
In a preferred embodiment, the antenna assembly has a substantially non-conductive covering that is preferably at least partially deformable. The substantially non-conductive membrane is preferably comprised of at least one of rubber, plastic, non-metallic tubing, an adhesive, or a non-metallic substrate. In a preferred embodiment, the antenna assembly has a deformable membrane, wherein the deformable membrane has a substantially flat body having a base edge and a crest edge opposite to the base edge, wherein the at least one transmission line emerges from the base edge of the deformable membrane, the at least one deformable conductor is disposed within the body of the deformable membrane, and the at least one dipole antenna is at least partially enclosed within the crest edge of the deformable membrane. Even more preferably, the crest edge has a thicker cross section than the body of the deformable membrane. The body of the deformable membrane may be at least partially coated on at least one side with an adhesive substance. The at least one antenna is, preferably, deformable.
In another preferred embodiment of the invention, the antenna assembly is mounted between bricks or stones in masonry, or in a groove cut into a solid surface. In a more preferred embodiment, an antenna assembly as described above is mounted or fixed between bricks or stones in masonry or in a groove cut into a solid surface with at least a portion of the deformable membrane fixed between opposing edges of the bricks, stones, or groove, and with the at least one transmission line behind the solid surface. In an even more preferred embodiment, the antenna assembly as described above has a crest portion that is disposed flush with or no more than about xc2xc inch in front of the solid surface.
In another alternative embodiment, the antenna assembly has a deformable membrane, wherein at least part of the deformable membrane is ring-shaped and is sized to elastically encircle a periphery of a cover that fits into a surround. The size of the ring-shaped portion may be equal to or smaller than the circumference of the cover, and when the size is smaller, the contractile force of an elastic deformation required to stretch the ring-shaped portion around the outer periphery of the cover provides sufficient force to secure the antenna assembly to the cover. In a preferred embodiment, the cover is a traffic surface cover. In an even more preferred embodiment, the cover is a manhole cover and the surround is a manhole ring. The ring shaped portion of the deformable membrane may be at least partially coated on at least one side with an adhesive substance.
The at least one transmission line may also be connected to a transmitter or receiver or transceiver. Optionally, the antenna assembly includes an adhesive material that is affixed to at least a portion of the substantially non-conductive membrane. In an embedded or flush application, the antenna may be fixed to and sealed within the mounting surface by epoxy formulations specialized for sealing the type of surface the antenna is being positioned on or within. An antenna assembly of the present invention may be removably or permanently fixed to the mounting surface. When permanently fixed to the mounting surface, the antenna assembly may be at least partially embedded in a permanent adhesive that fills a gap or crevice into which the antenna assembly is at least partially inserted.
In another embodiment, the present invention provides an antenna assembly as described above or below further comprising at least one transceiver. In preferred embodiments, the at least one transceiver is substantially enclosed within the deformable membrane. In more preferred embodiments, the at least one transceiver is conductively connected to the at least one antenna of the antenna assembly.
The present invention is also directed to methods of installing an antenna assembly in a crevice or gap, particularly in a crevice or gap of an aperture or in a crevice of an aperture closure, or in a crevice of a closure. In one embodiment, the present invention provides a method of installing an antenna assembly in a closure, comprising: opening the closure sufficiently to provide a gap; disposing within the gap at least a portion of an antenna assembly, the antenna assembly; and closing the aperture to fix the antenna assembly in place. The antenna assembly may be an antenna assembly as described above or below. In this embodiment, the at least one antenna is preferably deformable.
In another embodiment, an antenna assembly as described above or below is fixed in a solid surface by a method comprising cutting a groove into a solid surface and fixing at least a portion of an antenna assembly within the groove. In another embodiment, an antenna assembly as described above or below is fixed in a solid surface during construction of the solid surface. In particular, during the laying of masonry (i.e., stones, bricks, cinderblocks, or the like), at least a portion of an antenna assembly is disposed between adjacent masonry units, is fixed in place with mortar or other adhesive, and becomes a permanent fixture in the masonry. Even more preferably, the at least one transmission line emerges from one side of the masonry, preferably the inside or behind the masonry. Most preferably, the antenna assembly comprises a crest edge that is disposed about flush with and no more than about xc2xc inch in front of the masonry.
The present invention also provides a method of installing or fixing an antenna assembly in a traffic surface, comprising: providing a traffic surface comprising a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface; removing the cover from within the surround; disposing adjacent to at least a portion of an inner periphery of the surround at least a portion of an antenna assembly as described above or below; and replacing the cover within the surround such that the at least a portion of the antenna assembly is fixed between at least a portion of the cover and the at least a portion of the inner periphery of the surround. In an alternative embodiment, a gap or crevice is formed between especially tight-fitting cover and surrounds, for example by grinding away a portion of the outer periphery of the cover or the inner periphery of the surround, in order that an antenna assembly of the present invention may be disposed therethrough.
The present invention also provides a method of installing or fixing an antenna assembly in a traffic surface, comprising: providing a traffic surface comprising a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface; removing the cover from within the surround; adhering at least a portion of an antenna assembly, as described above or below, but wherein the deformable membrane is at least partially coated on at least one side with an adhesive substance, to either at least a portion of an outer periphery of the cover or at least a portion of an inner periphery of the surround; and replacing the cover within the surround such that the at least a portion of the antenna assembly is sandwiched between at least a portion of the cover and at least a portion of the inner periphery of the surround.
The present invention further provides a method of installing or fixing an antenna assembly in a traffic surface, comprising: providing a traffic surface comprising a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface; disposing adjacent to at least a portion of an inner periphery of the surround at least a portion of an antenna assembly, the antenna assembly comprising: at least one antenna; at least one transmission line; at least one conductor for conductively connecting the at least one antenna to the at least one transmission line, wherein the at least one conductor is deformable; and a deformable membrane made from substantially non-conducting material substantially covering the at least one antenna and the at least one conductor, and at least partially enclosing the at least one transmission line; wherein the deformable membrane has a substantially flat body having a base edge and a crest edge opposite to the base edge; wherein the at least one transmission line emerges from the base edge of the deformable membrane, the at least one conductor is disposed within the body of the deformable membrane, and the at least one antenna is at least partially enclosed within the crest edge of the deformable membrane; and wherein the crest edge has a thicker cross section than the body of the deformable membrane; so that the crest edge is disposed above the traffic surface but no more than about xc2xc inch above the traffic surface, at least a portion of the body of the deformable membrane is disposed across the inner periphery of the surround, and the at least one cable extends below the surround; and replacing the cover within the surround such that the at least a portion of the body of the deformable membrane is clamped between at least a portion of the outer periphery of the cover and the at least a portion of the inner periphery of the surround, and such that the crest edge is disposed above, but not more than about xc2xc inch above, the traffic surface, and the at least one cable extends below the traffic surface. Prior to replacing the cover, the at least one transmission line may be connected to a transceiver or other instrument disposed below the traffic surface.
In a more preferred embodiment, the present invention provides a method of installing or fixing an antenna assembly in a traffic surface, comprising: providing a traffic surface comprising a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface; providing an antenna assembly as described above or below, but wherein the body of the deformable membrane is at least partially coated on at least one side with an adhesive substance; adhering at least a portion of the body of the deformable membrane of the antenna assembly to at least a portion of an outer periphery of the cover or an inner periphery of the surround so that the crest edge is disposed above the traffic surface but no more than about xc2xc inch above the traffic surface, the at least a portion of the body of the deformable membrane is disposed across the outer periphery of the cover or the inner periphery of the surround, and the at least one transmission line extends below the cover or surround, and replacing the cover within the surround such that the at least a portion of the body of the deformable membrane is fixed between the at least a portion of the outer periphery of the cover and at least a portion of the inner periphery of the surround or the at least a portion of the inner periphery of the surround and at least a portion of the outer periphery of the cover, such that the crest edge is disposed above, but not more than about xc2xc inch above, the traffic surface, and the at least one cable extends below the traffic surface. Prior to replacing the cover, the at least one transmission line may be connected to a transceiver or other instrument disposed below the traffic surface.
Alternate embodiments of the present invention, as described above, provide methods of installing or fixing an antenna assembly in a traffic surface wherein at least part of the deformable membrane of the antenna assembly is ring shaped and is sized to elastically encircle the periphery of the traffic surface cover, and wherein the body of the deformable membrane may be at least partially coated on at least one side with an adhesive substance; and wherein at least a portion of the antenna assembly is disposed around or adhered to an outer periphery of the cover. In such embodiments, the ring-shaped portion of the deformable membrane may act further as a gasket between opposing edges of the cover and surround where the antenna assembly is installed, and may act to seal the aperture against the entry of environmental contaminants. In another such embodiment, the ring-shaped portion of the deformable membrane may be embedded within an adhesive or sealant, either removable or permanent, that at least partially fills the gap or crevice into which the antenna assembly is fixed.
The present invention further provides an apparatus, comprising: a gap in a solid surface having an antenna assembly, as described above or below, removably or permanently fixed within a gap of the solid surface.
The present invention also provides an apparatus, comprising: a closure having an antenna assembly, as described above or below, removably or permanently fixed within a gap of the closure.
In a preferred embodiment, the present invention provides an apparatus, comprising: a traffic surface comprising a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface; and an antenna assembly, as described above or below, removably or permanently fixed between at least part of an outer periphery of the cover and at least part of an inner periphery of the surround.
In an even more preferred embodiment, the present invention provides an apparatus, comprising: a traffic surface, comprising a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface; and an antenna assembly as described above or below removably fixed between at least part of an outer periphery of the cover and at least part of an inner periphery of the surround, wherein the crest edge is disposed above the traffic surface but no more than about xc2xc inch above the traffic surface, at least a portion of the body of the deformable membrane is disposed between the at least part of the outer periphery of the cover and the at least part of the inner periphery of the surround, and the at least one transmission line extends below the traffic surface. The at least one transmission line is preferably connected to at least one transceiver or other instrument. Even more preferably, the at least one transceiver or other instrument is below the traffic surface.
Even further, the present invention provides a method for sending and receiving RF signals from within a gap in a solid surface or behind a closure, comprising: providing an antenna assembly, as described in any of the embodiments above or below, fixed within a gap or closure, preferably between opposing edges of the gap or closure; providing at least one RF signal transceiver; connecting conductively the at least one RF signal transceiver to the at least one antenna by conductively connecting the at least one RF signal transceiver to the at least one transmission line; and transmitting or receiving RF signals using the antenna assembly. The transceiver is preferably behind the solid surface or closure, and the antenna assembly preferably has a low profile with respect to the side of the solid surface or closure opposite to the transceiver, i.e., in front of the solid surface or closure.
In a more preferred embodiment, the present invention provides a method for sending and receiving RF signals, comprising: providing an antenna assembly, as described in any of the embodiments above or below, removably fixed to a traffic surface, wherein the traffic surface comprises a cover and a surround adapted to receive the cover in an orientation substantially flush with the traffic surface, between at least part of an outer periphery of the cover and at least part of an inner periphery of the surround; providing at least one RF signal transceiver of other instrument; connecting conductively the at least one RF signal transceiver or other instrument to the at least one antenna by conductively connecting the at least one RF signal transceiver or other instrument to the at least one transmission line; and transmitting or receiving RF signals using the antenna assembly. Preferably, the transceiver or other instrument is situated below the traffic surface.
The present invention may be used favorably in a variety of locations. The antenna assembly of the present invention, as described above or below, may be installed in any gap, crevice, openably closed aperture, or closure. In a preferred embodiment, the antenna assembly of the present invention may be installed in any gap, crevice, aperture, or closure providing access to an enclosed system or network, such as a storm sewer network, sanitary sewer network, or air handling network. Examples of such apertures and closures include apertures and closures in traffic surfaces, such as roadways, sidewalks, decking, floors, and stairways, such apertures and closures including storm sewer gratings, utility access points and manholes and the like, and apertures and closures in other enclosed networks such as ductwork, such apertures and closures including access panels, doors, windows, grills, screens, and the like. In more preferred embodiments of the above, the apertures and closures comprise a cover and a surround, and even more preferably the cover is a manhole cover and the surround is a manhole ring.
In some of the various embodiments of the present invention, the at least one antenna may be a dipole antenna. In preferred embodiments, the antenna assembly of has at least one antenna, wherein the at least one antenna is a dipole antenna and comprises first and second elongated elements separated by a gap, and the first and second elongated elements are positioned to extend in substantially opposite directions from one another and to form a substantially straight line. In more preferred embodiments, the substantially straight line has a length that corresponds to an operating frequency band of the at least one antenna, and the length provides an electrically tuned antenna that is configured to transmit and receive RF signals in close proximity to a surface.
In other of the various embodiments of the present invention, the at least one antenna may be a dipole antenna, wherein the at least one dipole antenna comprises first and second elongated elements separated by a gap, and the first and second elongated elements are positioned to extend in substantially opposite directions from one another and to form a circumferentially-curving line, and wherein the circumferentially-curving line has a length that corresponds to an operating frequency band of the at least one antenna. In even more preferred embodiments, the length provides an electrically tuned antenna that is configured to transmit and receive RF signals in close proximity to a surface.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting in any way.
As such, those skilled in the art will appreciate that the concept and objectives, upon which this disclosure is based, may be readily used as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.